A thermosetting resin having an oxirane group or an oxetane group has excellent heat resistance, mechanical strength (rigidity), and/or workability, and thus it is widely used as an electronic and electrical component, a molding material, a laminate, a sealing material, and the like. However, a history of cooling and heating, and the like sometimes causes cracks in the resin. As a countermeasure for the cracks, a method for adding a plasticizer to the material is generally used. However, the method has such problems that, depending on the plasticizer added, heat resistance and/or strength (modulus of elasticity) of the material deteriorate, that the plasticizer added bleeds out from the material, and the like.
On the other hand, a polyrotaxane exhibits characteristics such as viscoelasticity, a lower compression set and the like in a crosslinked body of polyrotaxanes with each other, a crosslinked body between a polyrotaxane and the like and a polymer other than polyrotaxane, due to movement of cyclic molecules, which constitute the polyrotaxane, on a linear molecule. Since the polyrotaxanebecause can provide these characteristics, the polyrotaxane is expected to offer various applications, and research and development thereof is carried out actively.
For example, Patent Document 1 discloses a crosslinked body obtained by crosslinking a polyrotaxane with a polymer other than polyrotaxane. It also discloses crosslinking a polyrotaxane with a polymer via a crosslinking agent.
Further, Patent Document 2 discloses dispersing a polyrotaxane in a thermosetting resin such as an epoxy resin and a polyimide resin, to raise the glass transition temperature of the thermosetting resin, and to relax stress thereof at below the glass transition temperature. However, the Patent Document 2 does not disclose crosslinking the polyrotaxane with the thermosetting resin via a chemical bond.
More, Patent Document 3 discloses a polyrotaxane wherein cyclic molecules of the polyrotaxane are substituted with -M-A, -M-B, and -C (M represents a polymer portion; A represents a functional group such as a hydroxyl group, an amine, and the like; B represents a hydrophilic group such as a carboxyl group and the like; and C represents A or C).
A polyrotaxane can relax internal stress which is generated upon crosslinking in a crosslinked body and the like between the polyrotaxane and a polymer other than a polyrotaxane, and can be expected to improve brittleness caused in the polymer other than polyrotaxane. Therefore, by adding a polyrotaxane into a thermosetting resin having an oxirane group or an oxetane group, followed by crosslinking them, the polyrotaxane can be expected to play a role as a large movable crosslinking agent in a crosslinked network of the thermosetting resin.